Filter shell



July 25, 1944. I K. US ELL 2,354,481

FILTER SHELL Filed Oct. 5. 1942 5O 45 ri'gfenul 1Q" 67 v l/v v/vroze JOHN K./Quss1 1.

HA 1;} Mic/4,535 TERcQHAAR/S FOR HE F/AM Patented July 25, 1944.

m'rsn'snann f John K. Russell. Los Angeles, calla. nllllnor to Luber-Fin'er, Inc., Los Angeles', Calii'., a corporation of California I [Applicati n October s; 1942, Serial No. 460,895 I My invention relates to filter devices, particularly devices'for filtering liquids, and is directedp specifically'to the construction of a shell to serve as a filtering wall. The inventionis being initial-- 7 1y applied to the'construction of a filterelement for service in thelubricating system of an auto- 7 I strength andrigidity. I have further discovered that perforated cardboard or thick paper that is v suitably oil-resistant maybe used, and have found that twoj or more layers of such perforated paper provide adequate strength for the side wall of the filter element and adequate supportffor .th

motive engine and will be sodescribedfor the purl pose of; the present disclosure; t

A filtering system of the type under consideration, for use in automobiles for example, includes a permanent-,met'al housing through which at least aportion of the engine lubricating oil is con.- tinuouslyj'passed for filtering action. Inside the permanent housing is mounted a filter pack or I element, the arrangement being such thatthe flowing oil is subject tofilter action both by the cylindrical wall of the filter element and by filter material contained in the element. The filter element may be renewable or replaceable in whole or in part, The present construction is directed to the construction ofsuch afilter .ele-L ment with special reference to the construction of the filtering shell'or outer wall. 1

7 It is one object of my invention to provide a": simple but. efllcient filtering shell that is inexpensive to manufacture and is adapted for mass production.. It is another obiect of the invention to provide a filtering shell'at such low cost that associatedsheetof'filtering material. 7

One of the problems it is my purpose to solve in Q the preferred practice of the;invention is that of providing for sufficient flow-openings through a dual layer perforate wall. For economy in, menufacture the sheets of oil-impervious paper must be perforated before being formed to "cylindrical configuration, but if such sheets 'are pre-perforated the problem arises of how toinsure proper registration orwoverlap of the perforations of the I v two layerss superimposing two perforated sheets I a indiscriminately mayprovide either a very small.

total area of overlappingapertures or may result in substantial registration of the apertures of both '1. sheets. it is myobiect to .provide a method of superimposing one perforated sheet on another the whole filter element, of'which theshell is a.

part, may be discarded. entirely andeconomically replaced by an entirely new. filter element at the end of a normal period of service. Another object of theinvantion is to provide a filtering. v shell that may be manufactured with minimum use of metals or other'materials that are rel atively expensive or relatively diflicult to attain,

especially in wartime.

1 substantially radial or normal thereto and atthef sametime to provide extensive areas in which .The contemplated filtering shell must havesufa ficient strength and rigidity toserve as the side. wall of the filter element, must be so constructed "as to perform the desired filtering function, and

moreover, must provide a fiow capacity adequate in the manufactureof a filtering shell that may be 7 carried out with rapidityand with nocare for v registration of apertures and yet will-result in substantially a predetermined total area of aperture overlap.

It is another object of my invention to provide.

a filtering shell that will afford an effective filtering action. .It is one of my purposes to provide both extensive areas on the wall of the filter pack in which the oil fiow through the filtering wall is the filter flow through the wall isnon-radial.

In the preferred practice of my invention I have the specific object of providing sufficient areas of radial flow of relatively:lowfiow-resistanceadequate for the contemplated rate of flow of oil through the'filter housing; itvbeing contem-' plated that initial flow will be largely radial, nonfor the desired rate of oil fiow. Sincethe filter element is to be discarded aftera period of ser-' 7 vice, both the material of 'thecylindrical filtering shell and the method of fabricating the shellmust be inexpensive. My preferred construction meets these requirements and in addition meets-the. problem ofminimizing the use of scarce materials.

' ingdra'wing. t In the drawing, which is to be considered as 11- I have discovered that a suitable shell may be Q fabricated by using non-metallic perforated sheet I material incombination with a sheetof'filtering material, more. than one layer of the perforated sheetbeing employed to obtain the desired radial-flow along the paths of greater resistance increasing as the paths of radial flow become increasingly clogged'b'y filtrate.

The above and other objects and advantages of I my invention will be apparent from the detailed description to'follow, taken with the accompanylustrative only V Fig. '1 15a sectional'view of filtering apparatus for an automobile incorporating my invention, 1 fragments of my filtering shell being shown in c side elevation;

' mounted in a small bracket 41.

Fig. 2 is a perspective View of a spider employed in the permanent housing shown in Fig. 1; v Fig. 3 is a fragmentary perspective view of the inner surface of the upper portion of the hous- 8;

Fig. 4 is a transverse section taken as indicated by the line 4--4'of Fig. 1;

Fig. 5 is a development of a strip of the filtering shell shown on an enlarged scale; and Fig. 6 is an enlarged portion of Fig; 5. [The drawing shows a permanent filter housing generally designated III of a well-known type commonly employed for purifying the oil in the lubricating system of an internal combustion engine. The filter housing l0 has a cylindrical side wall il, a bottom wall I2 unitary therewith and is fitted with a cover I! having a sealing gasket l5. 7

Formed in the cylindrical side wall II is an inwardly presented rib l5, immediately above which is a latching ring I]. The latching ring I! is' of U shaped configuration providing two cylindricalfianges 18 for anchorage to the surrounding cylindrical wall ii of the housing ill. The latching ring I] is cut away fromabove to provide three circumferenti'ally spaced bayonet slots 20 best shown in Fig. 3, each bayonet'slot having an entrance 2| and a latching portion 22.

The cover I3 hasan axial opening '23 through which extends a suitable threaded member such as a cap screw 25, there being a suitable packing ring or gasket for sealing action between the" head of the cap screw and the outer surface of the cover. The'cap screw is threaded into the threaded axial bore' 21 of a suitable spider 28 having three latching legs corresponding to parent that the spider 25 may be engaged with the bayonet slots 25 and the cap screw 25 tightened to close the filterhousing l0 in a substantially liquid-tight manner.

The bottom wall II of the filter housing I5 is preferablyreiniorced by a plate 3| having upwardly turned reinforcing flanges 52. Extending through both the bottom wall 2 and the reinforcing plate 3| is a drain plug 33, a threaded inlet-fitting 35 and a central threaded outlet fitting 35, which outlet. fitting carries an upwardly extending nipple (on its inner end. Mounted on the nipple 31 is a filter element generally designated 40 to which the present invention especially refers. A number of indentations 4| may be made in the side wall of the filter housing III to form multiple supports for the bottom of the filter element 40 as indicated in Fig. 1.

While I prefer to use with my filter element the described filter housing I0, it will be readilyunderstood that any other type of construction of filter housing may be employed in various practices of my invention.

The filter element 40 has an imperforate top wall 42, an imperforate bottom wall 45, and a perforate cylindrical side wall or filtering shell 45. The top-wall 42 may be fabricated from sheet metal or suitable plastic and preferably is provided with a suitable bale or handle 45 pivotally The top wall 42 may be united with the filtering shell 45 in any suitable manner. In the present constructionthe circumferential margin of the top wall is formed to a U-shaped cross-sectional configuration to The imperforate bottom wall 43 of the filter element may be of the same material as the top wall and in like manner may provide an annular recess 48 to seat the lower end of the filtering shell 45. On the inner face of the bottom wall 43 is seated a cup 50 and inside the cup is an upwardly presented cap 5|, the cup and cap being made of suitable thin-walled material. A threaded outlet fitting 52 extends through the three layers of. material provided by the bottom wall 43, the cup 50, and the cap 5|, the three layers of material being securely gripped between an annular shoulder 53 on the circumference of the outlet fitting .and a radial flange 55 on the lower end of the outlet fitting. Such a radial fiange 55 may be formed by a spinning or swaging operation; The outlet fitting 52 is suitably threaded for engagement with the previously mentioned nipple 31 as best shown in Fig. 1,, the arrangement being suchthat the filter element 45 is supported both by the nipple and by the indentations 4|.

The numeral 56 generallydesignates a filter tube or means for receivingfiltered liquid for now to the outlet fitting 52. Such afilter tube 55 may be constructed in'any suitable manner to hold back-solid material, butfpermit relatively free flow of liquid. In my preferred construction the filter tube 55 comprises one or more layers 51 of cheesecloth 'or like material and one or more layers 55 of perforate sheet material; An upper cap 5| is pressed --upon the upper end of the filter tube 55 and the lower end of the filter tube is pressed into the seatprovided by the lower cap. 5|. Preferably, the filter element 40 is filled with a suitable filter meduim 52 surrounding the filter tube 55. The filter medium 52 may consist of clay, fiber, or other materials known to the art.

In normal operation of the filter system, oil entering the-housing l0 through the inlet fitting 35 surrounds the filter element 40, passes through the filtering shell 45, the filter medium 52, and the wall of the filter tube 55, to flow downward and outward through the nipple 31 and the outlet fittin 35.

In my preferred-procedure for fabricating a cylindrical filtering shell 45 having a diameterof approximately 5", I employ what is known as tag board approximately thick. This wellknownsheet material is a processed paper with a glossed surface and is what may be termed oilresistant, since it will retain its form and strength over a prolonged period of contact with oil. I

' mately twice the circumference of the contemof the desired diameter.

' sheetvrelative to the perforations of the other turn of the sheet is such that a range from substantially no registration of perforations to subprovide an annular recess 48 to receive the upper end of the filtering shell 45. v

stantially full registration of the perforations corresponds to the circumference of the cylinder, and if the perforations are so spaced that a perforation in one turn of the sheet'cannot overlap simultaneously two perforations in the other turn of the sheet, the total area unmasked by over- ;12 indicates a lapping of perforations will be substantially half the total area of the perforationsof one turn of thesheet, since the average overlap'will be ap proximately one-half. If the rangeofprogresl sion from minimum is one-half, one-fourth, or any even part of the overlap to maximum overlap circumference, the total area unmasked will like- 7,

perforations are so spaced thata perforation in one turn of thesheet may overlap simultaneously two perforations in the other. turn .theratio of unmaskedareato masked area will be'increased by an amount that may be readily estimated. 7

In my preferred practice therange of progres-.

sion from minimum} overlap to maximum overlap H is approximately one-fourthof the circumference.

and one perforation in one turn may-overlap the perforations in-the other tum. Prior to rolling I superimpose ononeside; thereof a layer, of filtering material, for example,

the perforated sheet a sheet of suitable filter paper,,the length'of'the wise be approximately one-half of the total area ofr l perforations in one turn of the sheet. If the layer being approximately equal to the circum ferenceof the contemplated cylindrical shell. I then roll the perforated sheet with. the-superimposed filter sheet to the spiral configuration,

thereby forming two-layers of the perforated ma-i terial withthe sheet of. filter paper sandwiched therebetween. Preferably sufficient material of the two sheetsis provided to permit overlap'of the ends as required for structural strength and filter ing efficiency. The filtering shell. thus formed is assembled to the previously described bottom wall 43; the filter tube 56 with its upper'oap 6! is mounted on the bottom wall :the filter medium 62 is then placed inside the filter shell 45; and

then the upper wall 4 2is assembled to the'filter shell to complete thefilter unit. Fig. 1 shows the completed filter unit in place and showsa spirally wound perforated sheet with the perforations 83, the sheet being rolled to two turns forming an inner turn or layer 66' and an outer turn or layer 61, the two turns supporting and holding in place.

the intermediate sheet 68 of filter paper.

Themanner in which the perforations of the two turns of the spirallywound perforated sheet 85 progressively overlap is indicated by Figs. 4, 5, and 6. In Fig. 5 the circles in solid lines are perforations in one turn of the perforated sheet 65, the dotted circles represent perforations in the other turn of the sheet, and the shaded areas are the areas of overlap of perforations.

. clinedfiwith'respectto the circumference of: the

Arrow ll represents a condition inwhlch the exposedareas on. the intake side ofthefilter layer flare clogged to such'an extent thatoil is forced face of theouter perforated layeriltoreach a lesser clogged portion of to fiow along the inner.

the filter sheet.

Since the intermediate. filter sheet 68 is merely imprisoned by the two perforated layers 86 and 61, andis not directly bonded to the two layers, the type of fiow indicated by the arrow 12 is facilitated.

While I have described 68 and 61, my invention contemplates the provision of thesheet 65 of greater length to provide more than two layers or turns, particularly when the diameter of the filter shell is greaterthan five inches, and also when the diameter of the filtering shell is five inches or.less and: greaterv resistance to deformation .of the filter shell is desired. Likewise, while the: perforations fl'in the sheet 65 areillustrated in the, drawing as circular in form, my.-inv ention contemplates per forationsof any desired shape, for example, elongatedslotswhichmay be provided with their axes circumferentiallydisposed of the shell 45 or inshell 45. I have found. that 'diagonal'slots ap-.

proximately one-eighth: inch by three-eighths inch may be effectively employed in'theformation' of afilter shell of approximately five-inches diameter. 7

As hereinbefore described and as illustrated in the drawing, the filter tube 56 terminates below the top. wall '42 ofthe filter element 40 and is.

secured only to thebottomwall 43., It iswithin the scope of my inventionto secure the filter tube to both thetop wall 42 and the bottomwall 43, or to only the top wall 42, and to cause the filter tube 56 to communicate with the exterior of the filter element 40 through the top wall 42 instead of the bottom wall 43, or to communicate with the exterior of the filter element 40 through both the top wall 42 and the bottom wall 43.

The preferred practice and embodiment of my invention set forth hereinfor. the purpose of disclosure are to be considered as illustrative only. It will be apparent to those skilled in the art that various changes and substitutions may be made under my inventive concept, and I reserve the right to all such departures from my description It is contemplated that the total unmasked outer surface of the filter sheet exposed by per-- forations in theouter turn of the turn of the perforated sheet 65. As such clogging progressively increases with resultant increase in resistance to simple radial flow non-radial flow progressively increases but with very little reduction in total flow. Arrow 10 in F3. 6 indicates a path of simple radial fiow; arrow 1! indicates a path of non-radial flow that is followed when clogging substantially reduces direct radial flow; and arrow that lie within the scope of my appended claims. V

I claim as my invention:

1. A filter shell forum in a lubricating system, comprising: a sheet of oil-proof paper rolled to turns of a spiral to form multiple layers of a cylindrical wall, there being sufficient turns to make the wall self-supporting; and fibrous filter material in sheet form interposed between layers of said wall, said layers being perforated to permit flow through said filter material.

2. A filter shell for use in an oil purifier housing of a lubricating system, comprising: a sheet of. substantially oil-proof paper rolled to turns:

of a spiral to ,form the inner' andv outer layers of a cylinderyand a sheet of filter material interposed between said inner and outer layers, said sheet of oil-proof paper having numerous perforations substantially uniformly spaced circumferentially so that the progressive change in diameter resulting from the spiral curvature of the oil-proof paper causes progressively varying overlap of the perforations of the.inner andouter layers of the cylindrical wall.

type ot filtering flow that may 1' I occurl after substantial clogging has occurred.

V the filtering shell 45 as formed ofthe sheet;65 =in* two layers or turns 3. A filter shell for use at a given rate of filter flow in an oil purifierhousing of a lubricating system, comprising: a sheet oI-substantial-ly oilproof paper rolled to'two turns of a spiral to form the inner and outer layers or a'cyllnder; and a sheet of filter material interposed between said inner and outer layers, said sheet of oil-proof paper having numerals perforations substantially uniformly spaced circumferentially so'that the progressive change in diameter resulting from the length of the desired shell and a length in excess of twice the circumference of said shell; placing a sheet of filterin material on the back of said a sheet of filtering material on the back of said sheet of oil-proof material, said sheet of filtering material having 'sufilcient length and width to cover all perforations exposed on theouter surface of the finished cylindrical shell; and rolling saidsheets into spiral form to form a cylinder of the desired size, the outer surface of which is wholly made up of said oil-proof material.

6. A method of fabricating a cylindrical filter shell, which comprises: perforating a sheet of 011- proof material having a width equal to the axial length of thedesired shell and a length in excess of twice the circumference of said shell; placing a sheet of filteringmaterial on the back of said sheet of oil-proof material, said sheet of filtering material having a width suillcient to cover the edge perforations in said oil-proof material and terial.

sheet of oil-proof material, said sheet of filtering material having 'a width sufilcient to cover the edge perforations in said oil-proof material and a length less than that of the sheet of oil-proof material by an amount equal to approximately the circumference-of the finished shell; and rolling said sheets into spiral form to form a cylinder of the desired size, the outer surface of which is whollymade upof said oil-proof material. 7 r

l 5. A method of fabricating a cylindrical filter shell, which comprises: perforating a sheet of oilproof material having a width equal to the axial length of the desired shell and a length in excess of twice the circumference of said shell; placing a length lessthan that of the sheet of oil-proof material'by an amount equal to approximately the circumference of the finished shell; and rolling said sheets into spiral form to'form acylinder of the desired size, the outer andinner surfaces of which 7. A method of fabricating a cylindrical filter shell, which comprises: perforating a sheet of oilproof material having a width equal to the axial length of the desired shelland a length in excess of twice the circumference of said shell; placing a sheet'of filtering material on the back of said sheet of oil-proof material, said sheet of filtering material havingsuillcient length and width to cover all perforations exposed on the outer surface of the finished cylindrical shell; and rolling said sheets into spiral form to form a cylinder of the desired size, the outer and inner surfaces of which are wholly made up of said oil-proof material.

JOHN K. RUSSELL.

are wholly made'up of said oil-proof ma- 

